Method of manufacturing a reflective element for a vehicular rearview mirror assembly

ABSTRACT

A method of manufacturing a reflective element for a vehicle rearview mirror assembly includes providing front and rear glass substrates and establishing an uncured trace material at least at the rear glass substrate and establishing an uncured seal material along a perimeter region of at least one of the second surface of the front glass substrate and the third surface of the rear glass substrate. The front and rear glass substrates are joined with the uncured seal material disposed therebetween. The uncured seal material and the uncured trace material are cured via a common curing process. The curing of the uncured trace material forms an electrically conductive trace at the rear glass substrate and the curing of the uncured seal material forms a perimeter seal of the reflective element. The electrically conductive trace is in electrical continuity with the electrically conductive mirror reflector.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent application Ser. No. 13/470,864, filed May 14, 2012, now U.S. Pat. No. 8,379,289, which is a continuation of U.S. patent application Ser. No. 13/033,951, filed Feb. 24, 2011, now U.S. Pat. No. 8,179,586, which is a continuation of U.S. patent application Ser. No. 12/580,499, filed Oct. 16, 2009, now U.S. Pat. No. 7,898,719, which is a continuation of U.S. patent application Ser. No. 12/260,499, filed Oct. 29, 2008, abandoned, which is a continuation of U.S. patent application Ser. No. 10/956,749, filed Oct. 1, 2004, now U.S. Pat. No. 7,446,924, which claims the benefit of U.S. provisional application Ser. No. 60/508,086, filed Oct. 2, 2003, which are hereby incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates generally to rearview mirror assemblies for vehicles and, more particularly, to rearview mirror assemblies that include one or more electronic components, such as electro-optic or electrochromic interior rearview mirror assemblies. However, aspects of the present invention may be equally suitable for use in prismatic rearview mirror assemblies and/or for exterior rearview mirror assemblies.

BACKGROUND OF THE INVENTION

It is known to attach a printed circuit board to an attachment plate adhered or otherwise affixed to a rear surface of a mirror element, such as an electro-optic reflective element assembly or a prismatic reflective element. In order to attach the printed circuit board to the attachment plate, various connectors or clips may be employed at the attachment plate and/or the circuit board. The attachment plate is typically adhered to the rear surface of the mirror element or substrate, such as via a suitable adhesive or tape or the like. The printed circuit board has a rigid printed board or substrate that is cut or formed to a desired form and has conductive traces and circuitry applied to or placed on or attached to the board. The attachment plate and printed board/substrate include multiple parts and components at the rear of the mirror element, which may be costly to manufacture and assemble. The multiple components also add to the size, weight and volume requirements for the circuit board, which thus may add to the size and weight of the mirror assembly. Also, the printed board or substrate material may add to the weight and to the cost of the mirror assembly.

Therefore, there is a need in the art for an interior rearview mirror assembly that overcomes the shortcomings of the prior art.

SUMMARY OF THE INVENTION

The present invention provides an interior or exterior rearview mirror reflective element assembly that includes a conductive trace and circuitry printed on and/or applied at or to the rear surface of the mirror reflective element assembly, such as to the rear surface of the rear reflective element substrate of an electro-optic or electrochromic mirror reflective element assembly or cell. The circuitry thus may be applied to the existing hard or rigid reflective element substrate (typically glass) of the mirror reflective element assembly, such that the reflective element assembly comprises a circuitry on glass arrangement (although the reflective element substrate may comprise other materials, such as acrylic or polycarbonate or the like, without affecting the scope of the present invention), and does not require the additional printed board or substrate and attachment plate of conventional mirror assemblies. The glass substrate or reflective element substrate of the mirror reflective element assembly thus provides the hard or rigid surface for the conductive trace and electrical components and replaces the hard or rigid printed board or substrate of conventional printed circuit boards. The circuitry on glass assembly of the present invention may be applied to reflective elements or reflective element assemblies of interior mirror assemblies, such as interior rearview mirror assemblies and the like, or of exterior mirror assemblies, such as exterior rearview mirror assemblies and the like, or of other mirror assemblies of vehicles, without affecting the scope of the present invention.

According to an aspect of the present invention, a reflective element assembly for a mirror assembly of a vehicle includes a reflective element substrate (typically glass) having a rear surface (the surface facing generally away from the driver of the vehicle and facing generally forwardly with respect to the direction of travel of the vehicle when the mirror assembly is installed to the vehicle) and a front surface (the surface facing generally toward a driver of the vehicle and generally rearward with respect to the direction of travel of the vehicle when the mirror assembly is installed to the vehicle). The reflective element assembly includes a conductive trace or layer disposed at the rear surface of the reflective element substrate and a non-conductive layer applied to the conductive trace and covering at least some of the conductive trace and leaving at least one portion of the conductive trace exposed. The reflective element assembly includes at least one circuitry component that is applied to at least one of the portions of the conductive trace.

The reflective element substrate may have a reflective layer disposed at one of the front and rear surfaces for viewing by a driver of the vehicle when the mirror assembly is installed to the vehicle. The conductive trace and at least one circuitry component thus are disposed at the rear surface of the existing rigid reflective element substrate (typically glass) that includes or is associated with the reflective surface of the reflective element assembly that is viewable by the driver of the vehicle.

For example, a third surface electro-optic or electrochromic transflective element assembly may include a metallic reflective coating or layer and one or more non-metallic, semi-conductive layers disposed at or on a third surface or front surface of the rear or second reflective element substrate. The rear reflective element substrate of the electrochromic reflective element assembly is positioned rearward of the front reflective element substrate, with an electrochromic medium disposed between the front and rear reflective element substrates. The third surface transflective element assembly thus may provide a reflective surface for viewing by the driver of the vehicle through the front reflective element substrate of the reflective element assembly. Alternately, a fourth surface electro-optic or electrochromic reflective element assembly may have a reflective coating or layer disposed on a fourth or rear surface of the rear reflective element substrate for viewing by a driver of the vehicle through the front and rear reflective element substrates or glass substrates of the reflective element assembly or cell. Alternately, the rear surface of a prismatic element or substrate may have a reflective layer disposed thereon or applied thereto for viewing by the driver of the vehicle.

In any of these embodiments, the conductive trace of the present invention may be applied at the rear surface of the rear reflective element substrate (or the rear surface of the single substrate for prismatic type mirror assemblies) and rearward of the reflective layer or coating so that the conductive trace and electronic components are not viewable by the driver of the vehicle through the reflective element substrate or substrates of the reflective element assembly. In applications where the reflective layer is disposed at the rear or fourth surface of an electro-optic or electrochromic reflective element assembly or cell, an insulating layer may be applied at the rear surface and over the reflective layer or layers, whereby the conductive trace may be applied to the insulating layer. The present invention thus utilizes the existing reflective element substrate of the mirror reflective element assembly as the rigid substrate for receiving the conductive trace and electronic components and/or circuitry.

According to another aspect of the present invention, a method of manufacturing a reflective element assembly for an interior rearview mirror assembly of a vehicle includes providing a reflective element substrate having a front surface and a rear surface. The reflective element substrate has a reflective layer disposed at one of the front and rear surfaces for viewing by a driver of the vehicle when the mirror assembly is installed to the vehicle. A conductive trace or layer is applied to or disposed at the rear surface of the reflective element substrate. A non-conductive layer is applied to the conductive layer to cover at least some of the conductive layer and to leave at least one portion of the conductive layer exposed. At least one circuitry component is applied to the at least one exposed portion of the conductive layer. The conductive trace or layer may comprise a conductive epoxy, such as a conductive silver epoxy or the like, and may be applied in a desired pattern onto the rear surface of the reflective element substrate.

The method may include providing the non-conductive material or layer or mask over portions of the conductive trace while exposing other portions or pads for receiving at least one accessory and/or circuitry component or the like, such as sensors, resistors, capacitors, display elements, and the like, thereon. Optionally, a display element, such as a light emitting diode (LED) display element, a vacuum fluorescent (VF) display element, an electroluminescent (EL) display element, a liquid crystal display (LCD) element, or a video display element or the like, may be integrally formed at the rear surface of the reflective element substrate, such that the display information is viewable through the reflective element substrate. Optionally, at least one proximity sensor or antenna may be applied to or clipped to or attached to or positioned along a portion of the rear surface of the reflective element substrate. The at least one proximity sensor or antenna may be operable to detect a presence of a person's finger at or near the mirror assembly, such as at or near one of the sensors or at or near a corresponding icon on or at the mirror casing or bezel and at which or behind which the proximity sensor is located. The circuitry or component may be operable to actuate a display menu or the like and/or actuate or toggle or control an accessory in response to such a detection.

The accessories or circuitry or electrical components may be applied or adhered to the exposed portions or pads of the conductive trace before the conductive trace has cured, such that the curing of the conductive trace may secure the accessories and the like to the conductive trace, or the accessories or circuitry or components may be adhered or secured to the exposed portions after curing of the conductive trace, without affecting the scope of the present invention.

The mirror reflective element assembly may comprise an electro-optic or electrochromic mirror reflective element assembly or cell having first and second reflective element substrates. The conductive trace may be applied to the fourth or rear surface of the second or rear reflective element substrate of the electrochromic mirror reflective element assembly. The electrochromic mirror reflective element assembly or cell may include clips or busbars extending at least partially along the upper edge of one of the reflective element substrates and the lower edge of the other of the reflective element substrates. The conductive trace may include portions that extend substantially to the upper and lower edges of the second reflective element substrate to facilitate connection to the clips or busbars. The clips or busbars may contact portions of the conductive trace applied to the rear or fourth surface of the rear or second reflective element substrate to connect the busbars to the circuitry or the like associated with or connected to the conductive trace.

Therefore, the interior rearview mirror assembly of the present invention provides a mirror reflective element assembly, such as an electro-optic or electrochromic mirror reflective element assembly or cell or a prismatic reflective element assembly, that includes a conductive trace and circuitry applied to or disposed at a rear surface of a reflective element substrate, such as a rear glass substrate of an electro-optic or electrochromic reflective element assembly or a single glass substrate of a prismatic reflective element assembly or the like, such that at least one electronic component and/or circuitry is integral with the reflective element substrate of the reflective element assembly. The reflective element assembly thus provides a circuitry on glass arrangement and thus utilizes the existing rigid glass reflective element substrate of the reflective element assembly as the rigid surface that receives the conductive trace and circuitry or electronic components thereon. The electronic components and/or circuitry thus are not provided on a separate rigid printed board or substrate that may be snapped onto or otherwise attached to an attachment plate adhered to or otherwise positioned at the rear surface of the reflective element. The rearview mirror reflective element assembly of the present invention thus provides a compact reflective element assembly, which may be readily manufactured, because the reflective element assembly does not include an attachment plate or the like. The mirror reflective element assembly of the present invention thus may provide a low cost, lightweight and compact reflective element assembly that provides for enhanced manufacturing and assembly processes.

These and other objects, advantages, purposes and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an interior rearview mirror assembly in accordance with the present invention;

FIG. 2 is a front elevation of a rear reflective element substrate of a reflective element assembly of the mirror assembly of FIG. 1, viewing through the reflective element substrate to show a conductive trace applied to the rear surface of the substrate;

FIG. 3 is a rear elevation of the rear reflective element substrate of FIG. 2;

FIG. 4 is an enlarged rear elevation of the rear reflective element substrate of FIGS. 2 and 3, with components and/or circuitry attached to the conductive trace;

FIG. 5 is a rear perspective view of an electrochromic mirror reflective element assembly having the rear reflective element substrate of FIGS. 2-4;

FIG. 6 is a sectional view of the electrochromic mirror reflective element assembly of FIG. 5;

FIG. 7 is a rear perspective view of a portion of a reflective element assembly of the present invention, with a light pipe attached between circuitry on the reflective element substrate and a bezel portion of the mirror assembly;

FIG. 8 depicts a cross-sectional view of another electrochromic mirror construction according to the present invention, and in this construction, a secondary weather barrier 112 has been applied to the joint at which sealing means 105 joins substrates 102, 103;

FIGS. 9A, 9B and 9C depict the orientation of the substrates in different constructions of the electrochromic mirrors and electrochromic devices of the present invention, with FIG. 9A depicting a perpendicular displacement of the first substrate and the second substrate, FIG. 9B depicting a lateral displacement and a perpendicular displacement of the first substrate and the second substrate, and FIG. 9C depicting an arrangement of the first substrate and the second substrate, wherein the dimensions of the length and width of the first substrate are slightly greater than those of the second substrate, and in this arrangement, the peripheral edge of the first substrate extends beyond the peripheral edge of the second substrate; and

FIGS. 10A and 10B depict cross-sectional views of electrochromic devices, which illustrate different seal constructions that may be employed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depicted therein, an interior rearview mirror assembly 10 includes a casing 12, a bezel 13, a reflective element assembly or cell 14 and a mounting arrangement 16 (FIG. 1) for adjustably mounting the casing and reflective element 14 to an interior portion of a vehicle, such as to a mounting button or the like at an interior surface of a windshield of a vehicle. Mirror reflective element assembly 14 includes a conductive trace or layer or coating 18 (FIG. 2) applied to or disposed on or at the rearward surface (the surface facing forward or in the direction of travel of the vehicle when the mirror assembly is installed in the vehicle) of a reflective element substrate, such as the typically glass substrate of the reflective element assembly, such as on the rear surface 20 a (FIGS. 3-6) of a second or rear substrate or glass element 20 of an electro-optic or electrochromic mirror cell (commonly referred to as the fourth surface of the electrochromic mirror cell). The reflective element substrate 20 thus may provide a substantially rigid surface for receiving the conductive trace and circuitry, and the reflective element assembly thus may comprise a circuitry on glass arrangement, whereby no separate rigid printed board or substrate or attachment plate is necessary to support the conductive trace and circuitry at the rear of the reflective element substrate of the reflective element assembly. However, the reflective element assembly and/or the mirror assembly may include other electronic elements or circuitry that may not be positioned or disposed on the glass surface, and/or that may complement the circuitry on the glass substrate, without affecting the scope of the present invention.

In the illustrated embodiment, the reflective element assembly 14 comprises an electro-optic or electrochromic reflective element assembly or cell that includes a front reflective element substrate 22 and the rear reflective element substrate 20. The rear reflective element substrate 20 is spaced from front reflective element substrate 22 with an electrochromic medium 21 and conductive or semi-conductive layers disposed or sandwiched therebetween, as is known in the electrochromic mirror art. The conductive trace 18 may be applied directly onto the rear surface 20 a (or onto an insulating epoxy or other type of layer or coating applied to the rear surface, as discussed below) of the reflective element substrate 20, and masking portions or layers of a non-conductive material 24 and circuitry components and/or accessories and the like may be applied directly to the conductive trace 18, such that no separate printed board and attachment plate and related components are required.

Although shown and described as an electrochromic reflective element assembly or cell, aspects of the present invention may be equally suitable for and applicable to a prismatic reflective element substrate and assembly or other types of reflective elements and assemblies, without affecting the scope of the present invention. Also, although shown and described as an interior reflective element assembly, aspects of the present invention may be equally suitable for and applicable to exterior mirror assemblies, such as exterior electrochromic rearview mirror assemblies and exterior rearview mirror assemblies with a single reflective element and the like, without affecting the scope of the present invention.

The conductive trace or layer 18 may comprise a conductive epoxy, such as a conductive silver epoxy or the like, that may be screen printed in a desired pattern or trace directly onto the rear surface 20 a of rear reflective element substrate 20 of reflective element assembly 14 (or onto an insulating layer or the like at the rear surface of the reflective element substrate). In FIG. 2, rear reflective element substrate 20 of reflective element assembly 14 is shown from the front side or surface 20 b, so that the conductive trace 18 is shown at the rear surface 20 a of reflective element substrate 20 by viewing through the transparent reflective element substrate 20.

If the mirror reflective element assembly or electrochromic cell 14 comprises a third surface reflective element assembly (where the front surface of the rear substrate, commonly referred to as the third surface of the reflective element assembly or cell, has a reflective and conductive metallic coating or layer or layers 39 a (FIG. 6), such as a silver or aluminum or chromium or rhodium or other metallic materials or alloys thereof, and one or more non-metallic semi-conductive layers, such as one or more layers of indium tin oxide (ITO), indium tungsten oxide (IWO), indium cerium oxide (ICO), indium oxide (IO) or the like, disposed thereon or applied thereto), the conductive layer or epoxy 18 may be applied directly to a clean glass surface at the rear surface of the rear reflective element substrate (or may be applied to an insulating layer or the like applied directly to the clean glass surface).

Alternately, if the mirror reflective element or electrochromic cell 14 comprises a fourth surface reflective element (where the reflective coating or layer 39 b (FIG. 6), such as a metallic layer or the like, is applied to the rear or fourth surface of the rear reflective element substrate of the cell), the protective paint layer or layers that are typically applied to the rear surface of the rear reflective element substrate may be replaced or covered with an insulating epoxy layer to provide an insulated surface at the rear of the rear reflective element substrate. The conductive trace 18 may then be applied to the insulating epoxy layer at the fourth surface of the reflective element assembly or cell.

The conductive epoxy layer may be applied as a conductive trace in the desired pattern onto the appropriate rear surface of the reflective element substrate. For example, the conductive epoxy may be screen printed onto the rear surface of the reflective element substrate in the desired pattern, such as shown in FIG. 2. Optionally, the conductive epoxy layer or coating may be applied over a substantial amount of the rear surface of the rear reflective element substrate and may function as an anti-shatter or anti-scatter element to limit or substantially preclude shattering/scattering of the glass reflective element substrate, such as in situations where the vehicle is involved in an accident or the like.

Optionally, the conductive trace and the mask or non-conductive layers and exposed pads or portions may be formed on the rear surface in a similar manner as it is typically formed on a conventional printed circuit board. For Example, a copper layer may be applied to the rear surface of the glass reflective element substrate and the masking or non-conductive layer may be screen printed onto the copper layer and etched away to form the desired pattern, without affecting the scope of the present invention.

After the conductive epoxy or trace has been screen printed or otherwise applied to the rear surface of the reflective element reflective element, the trace may be masked over with a non-conductive or masking layer 24 (FIGS. 3-5) that covers the conductive trace except at portions or pads 18 a (FIG. 3) of conductive trace 18 for affixing circuitry and components thereto, as discussed below. The non-conductive layer 24 may substantially cover the conductive trace except in areas where components or wires or accessories or the like may be positioned to provide the desired function to the reflective element assembly or cell 14. The components or wires or accessories (shown generally at 26 in FIGS. 4 and 6) may be affixed to the appropriate portions or pads 18 a that are exposed through the masking layer 24 to complete the circuitry that is integral with the mirror reflective element assembly or cell.

Also, after the conductive trace or epoxy layer has been screen printed or otherwise applied to the rear surface of the reflective element substrate, the conductive layer may be cured. It is envisioned that the conductive layer may be cured onto the rear surface of the reflective element substrate at the same time that the electrochromic reflective element assembly or cell is cured (such as at the same time that the epoxy seal 21 a (FIG. 6) that is disposed around the electrochromic medium and between the substrates is cured) to cure both the conductive epoxy layer and the epoxy seal of the electrochromic cell with the same curing process. The epoxy seal and the epoxy trace or layer may be cured via an air curing process or an oven curing process or the like, without affecting the scope of the present invention.

Optionally, the non-conductive layer and electronic components or circuitry may be applied to the conductive layer and pads or portions of the conductive layer before the conductive layer has been cured. The components may thus be temporarily affixed to the conductive pads, such as via adhesive dots or drops or the like applied (and optionally robotically applied) to the pads and/or the components, and then the reflective element assembly and epoxy seal and/or circuitry may be cured to secure the circuitry and components to the conductive trace applied to the rear surface of the mirror reflective element assembly. Such an approach provides for attachment of the components and curing of the conductive layer, and optionally of the epoxy seal of the reflective element assembly as well, in a single step, thereby substantially enhancing the manufacturing processes for manufacturing the electrochromic mirror reflective element assembly or cell.

The circuitry and components, such as resistors, capacitors, jumpers, and clips and the like, and accessories, such as sensors, display elements, such as light emitting diodes (LEDs), liquid crystal display elements (LCDs), vacuum fluorescent (VF) display elements, electroluminescent (EL) display elements or video display elements or other types of display elements or displays, sensors or antennae and the like, may be applied to and secured to the appropriate exposed pads or portions of the conductive trace, such as after the trace has been masked or covered by the non-conductive layer or material. Some of the electronic components or circuitry may also be screened or applied to the conductive trace. For example, it is envisioned that carbon ink resistors may be printed onto the conductive trace with another printing pass or screening pass. The carbon ink resistors may be applied utilizing lasers to tighten the tolerances to a desired level. This approach may reduce the need for separate resistors that would otherwise have to be applied during a later step. However, other known or conventional type resistors may be attached to the appropriate pads or portions, without affecting the scope of the present invention. In situations where circuitry paths need to cross over one another (in such situations, the other side of a printed circuit board is used to make such a cross over in a conventional printed circuit board), a zero ohm jumper or resistor may be attached to spaced apart pads or portions of the conductive trace to bridge or span the gap between the pads or portions and effectively cross over a portion of a conductive trace positioned between the spaced apart pads or portions.

Although described above as being applied directly to the rear surface of the reflective element substrate and being cured thereon, it is envisioned that the conductive trace may be applied to a substantially non-stick surface and cured thereon and then peeled from the surface and applied to the rear surface of the reflective element substrate as a pre-cured flexible conductive trace. This may be preferred in some applications to minimize the waste of conductive traces in situations where some of the reflective element assemblies may be discarded or scrapped due to defects in the reflective element assemblies. The conductive trace may then be applied to a reflective element substrate of a reflective element assembly or cell after the epoxy seal has been cured and after the reflective element assembly or cell has met the quality requirements. The conductive trace may be a flexible element that may be readily applied to or adhered to the reflective element substrate surface.

It is further envisioned that the conductive trace may be initially applied to the separate surface, and the non-conductive layer or masking and the circuitry and electronic components and accessories may be applied to the conductive trace, such as in the manner as described above. The pre-cured flexible circuit sheet may then be peeled from the surface and applied to or rolled onto the rear surface of the reflective element substrate. The busbars and other accessories or components may be connected to the appropriate exposed pads or portions of the conductive trace on the flexible circuit sheet either while the flexible circuit sheet is at the separate surface or at another surface, or after the sheet has been applied to the rear surface of the reflective element substrate. The flexible circuit sheet may be adhered to or bonded to or otherwise secured to the rear surface of the reflective element substrate via any suitable means, without affecting the scope of the present invention.

As discussed above, the rearview mirror reflective element assembly of the present invention may comprise an electro-optic or electrochromic reflective element assembly or cell, such as an electrochromic mirror reflective element assembly utilizing principles disclosed in commonly assigned U.S. Pat. Nos. 6,690,268; 5,140,455; 5,151,816; 6,178,034; 6,154,306; 6,002,544; 5,567,360; 5,525,264; 5,610,756; 5,406,414; 5,253,109; 5,076,673; 5,073,012; 5,117,346; 5,724,187; 5,668,663; 5,910,854; 5,142,407; and/or 4,712,879, which are hereby incorporated herein by reference, and/or as disclosed in the following publications: N. R. Lynam, “Electrochromic Automotive Day/Night Mirrors”, SAE Technical Paper Series 870636 (1987); N. R. Lynam, “Smart Windows for Automobiles”, SAE Technical Paper Series 900419 (1990); N. R. Lynam and A. Agrawal, “Automotive Applications of Chromogenic Materials”, Large Area Chromogenics: Materials and Devices for Transmittance Control, C. M. Lampert and C. G. Granquist, EDS., Optical Engineering Press, Wash. (1990), which are hereby incorporated by reference herein.

As shown in FIGS. 4 and 5, mirror reflective element assembly or cell 14 may include front reflective element substrate 22 and rear reflective element substrate 20 with electrochromic medium 21 sandwiched therebetween. The front reflective element substrate 22 has a front surface 22 a (the first surface of the electrochromic cell) and a rear surface 22 b (the second surface of the electrochromic cell), which may include one or more transparent semi-conductive layers (such as an ITO layer or the like, or such as disclosed in PCT Application No. PCT/US03/29776, filed Sep. 19, 2003 and published Apr. 1, 2004 as International Publication No. WO 2004/026633, which is hereby incorporated herein by reference) thereon. The rear reflective element substrate 20 may include one or more transparent semi-conductive layers (such as an ITO layer or the like), and/or a metallic conductive layer (such as a layer of silver, aluminum, chromium or the like or an alloy thereof), on its front surface 20 b (the third surface of the electrochromic cell), and may include multiple layers such as disclosed in PCT Application No. PCT/US03/29776, filed Sep. 19, 2003 and published Apr. 1, 2004 as International Publication No. WO 2004/026633, which is hereby incorporated herein by reference. The reflective element assembly 14 thus may comprise a third surface transflective element assembly or cell, whereby the reflective layer or surface is disposed at the third surface of the cell or at the front surface of the rear reflective element substrate for viewing by a driver of the vehicle.

Electrochromic reflective element assembly or cell 14 may include a front busbar or clip 30 that may engage or clip onto an edge portion (such as an upper edge portion 22 c) of front reflective element substrate 22 to provide electrical power or current to the semiconductive layer or layers on the rear surface 22 b of front reflective element substrate 22. The cell 14 may also include a rear busbar or clip 32 that may engage or clip onto an edge portion (such as a lower edge portion 20 c) of rear substrate 20 to provide electrical power or current to the semiconductive or conductive layer or layers on the front surface 20 b of rear substrate 20. The front clip 30 may include an extension 30 a that extends rearward over the rear substrate 20 and that engages a busbar pad 18 b at an upper portion of the conductive trace 18, while the rear clip 32 may engage a busbar pad 18 c at a lower portion of the conductive trace 18, such that electrical power or current may be applied to front clip 30 and to rear clip 32 to darken or color the electrochromic medium 21 as desired.

The extension 30 a of front clip or busbar 30 may be a separate extension attached to the clip or busbar, or may be integral with the clip or busbar, without affecting the scope of the present invention. The conductive trace 18 and exposed portions or pads 18 b, 18 c may extend to the upper and lower edges of the reflective element substrate and may act as a conductive rail along the edges so the clips 30, 32 may contact the conductive trace directly, with no wiring being necessary to connect the clips or busbars to the circuitry. The present invention thus may avoid the need to solder leads onto the busbars as is typically required with conventional busbars, such that the electrochromic mirror reflective element assembly of the present invention may provide for enhanced manufacturing processing. Optionally, an ASIC (application specific integrated circuit) die with external capacitors and clips may be applied at or near the upper and lower edges of the rear reflective element substrate for connection to the electrochromic clips or busbars 30, 32. Optionally, and as shown in FIG. 4, the extension 30 a may comprise a wire or lead that is soldered or otherwise conductively connected or secured to the busbar pad 18 b to connect an end or portion of the clip or busbar 30 to the busbar pad 18 b, without affecting the scope of the present invention. The clips or busbars and substrates and coatings may be configured and may function similar to known busbars and substrates and coatings, or may be of the types described in PCT Application No. PCT/US03/35381, filed Nov. 5, 2003 and published on May 21, 2004 as International Publication No. WO 2004/042457, which is hereby incorporated herein by reference.

The conductive trace 18 and electronic components and/or circuitry 26 may comprise or mount or attach one or more accessories, such as lights, a microphone, user actuatable controls or inputs, sensors, such as photo sensors or the like, or any other type of accessory suitable for such an application, as discussed below. For example, and as shown in FIGS. 4-6, one or more light sensors or photo diodes 34, 36 may be attached or mounted to appropriate exposed pads or portions 18 d (FIG. 3) of conductive trace 18, and may be operable to sense light at the mirror assembly. More particularly, light sensor 34 may be a forwardly facing (with respect to the direction of travel of the vehicle) sensor operable to detect the ambient light at the mirror assembly (such as via detecting light through an opening in the mirror casing or the like that receives light from forward of the mirror assembly and in the direction of travel of the vehicle), while light sensor 36 may be operable to detect glare at the mirror reflective element (such as by detecting light from rearward of the mirror assembly and from rearward of the vehicle). In order for light sensor 36 to detect the glare light rearward of the mirror assembly, it is envisioned that a window or transparent portion or area may be formed in the reflective layer or coating of the reflective element substrates to allow the sensor to view or receive light from rearwardly of the mirror assembly. Alternately, the light sensor may receive light that passes through the electro-optic reflective element assembly or cell, such as in display on demand or transflective cells and the like, without affecting the scope of the present invention.

Optionally, and with reference to FIG. 7, a light pipe 37 may be implemented to direct light through the bezel or casing of the mirror assembly and to bend the light, such as approximately 90 degrees or approximately 180 degrees (depending on the mounting orientation of the sensor) to direct or deliver the light to the sensor 36 at the circuitry on the back of the rear or second reflective element substrate, without affecting the scope of the present invention. In the illustrated embodiment of FIG. 7, the light pipe 37 functions to bend the light about 180 degrees to direct light from rearward of the mirror assembly (such as light at the bezel portion 13′ of the mirror assembly 10′) to the forward facing light sensor or photo sensor 36 at the conductive trace and circuitry 26 at the rear or fourth surface of the reflective element assembly. Optionally, the light pipe may extend between the circuitry and the back of an electrochromic reflective element assembly or cell where the light will be sensed/gathered/received from light passing through the cell, without affecting the scope of the present invention. Such an application may be suitable for use in applications with a transflective or display on demand type of cell. The sensors thus may face in generally the same direction on the circuitry, but may utilize light gathering means, such as one or more light pipes or the like, to gather and/or receive light from different directions, and may utilize aspects of the sensors described in U.S. patent application Ser. No. 10/229,573, filed Aug. 28, 2002, published Mar. 6, 2003 as U.S. Publication No. 2003-0043589, now U.S. Pat. No. 7,008,090, which is hereby incorporated herein by reference.

Although shown and described as comprising an electrochromic reflective element assembly, the present invention is equally applicable to prismatic reflective element assemblies and the like. For example, a conductive trace may be applied to a rear surface of a prismatic or wedge-shaped reflective element substrate, and electronic components and/or circuitry may be applied to the conductive trace, such as in a similar manner as described above, without affecting the scope of the present invention. The prismatic mirror assembly may comprise any type of prismatic mirror assembly, such as prismatic mirror assembly utilizing aspects described in U.S. Pat. Nos. 6,318,870; 5,327,288; 4,948,242; 4,826,289; 4,436,371; and 4,435,042; and PCT Application No. PCT/US04/015424, filed May 18, 2004 and published on Dec. 2, 2004, as International Publication No. WO 2004/103772; and U.S. patent application Ser. No. 10/933,842, filed Sep. 3, 2004, now U.S. Pat. No. 7,249,860, which are hereby incorporated herein by reference. Optionally, the prismatic reflective element may comprise a conventional prismatic reflective element or prism or may comprise a prismatic reflective element of the types described in PCT Application No. PCT/US03/29776, filed Sep. 19, 2003 and published Apr. 1, 2004 as International Publication No. WO 2004/026633; U.S. patent application Ser. No. 10/709,434, filed May 5, 2004, now U.S. Pat. No. 7,420,756; and U.S. provisional application Ser. No. 60/525,952, filed Nov. 26, 2003 by Lynam for MIRROR REFLECTIVE ELEMENT FOR A VEHICLE, which are all hereby incorporated herein by reference, without affecting the scope of the present invention. A variety of mirror accessories and constructions are known in the art, such as those disclosed in U.S. Pat. Nos. 5,555,136; 5,582,383; 5,680,263; 6,227,675; 6,229,319; and 6,315,421 (the entire disclosures of which are hereby incorporated by reference herein), that can utilize aspects of the present invention.

Optionally, the mirror reflective element assembly or cell 14 and electronic components and/or circuitry applied to the rear surface of the rear reflective element substrate may include display elements, such as for a display on demand type of display, such as of the types disclosed in commonly assigned U.S. Pat. Nos. 6,690,268; 5,668,663 and 5,724,187, and/or in U.S. patent application Ser. No. 10/054,633, filed Jan. 22, 2002, now U.S. Pat. No. 7,195,381, and/or in PCT Application No. PCT/US03/29776, filed Sep. 9, 2003 and published Apr. 1, 2004 as International Publication No. WO 2004/026633; and/or PCT Application No. PCT/US03/40611, filed Dec. 19, 2003 and published on Jul. 15, 2004 as International Publication No. WO 2004/058540, which are all hereby incorporated herein by reference.

With such a display, it is not only desirable to adjust the display brightness according to ambient lighting conditions, but it is also desirable to adjust the display brightness such that a sufficient contrast ratio is maintained against the variable background brightness of the reflected scene. Also, it may be desirable to compensate for changes in transmission of the electrochromic device to control rearward glare sources, so that the display brightness appears to be maintained at a generally constant level. The display and/or transmissivity of the electro-optic device may be adjusted to provide the desired function or viewability, such as by utilizing aspects of the systems described in U.S. patent application Ser. No. 10/427,026, filed Apr. 30, 2003, now U.S. Pat. No. 6,918,674, which is hereby incorporated herein by reference. Optionally, the circuitry 26 may include a light emitting diode (LED) array module or the like bonded or placed on or at or connected to the appropriate portions or pads of the conductive trace applied to the rear surface of the rear reflective element substrate and operable to emit light or display information through the mirror cell for viewing through the reflective element substrate or substrates by the driver or occupant of the vehicle. Other types of display elements may be implemented without affecting the scope of the present invention.

Optionally, and as shown in FIG. 6, the electrochromic mirror cell 14 may incorporate an integrated display element, such as a liquid crystal display (LCD) element 38, on or at the rear surface 20 a of rear reflective element substrate 20. Typically, a liquid crystal display element may include two sheets of spaced apart glass sheets with an appropriate conductive pattern printed on one of the surfaces of one of the sheets. The present invention may incorporate such a display on the rear surface of the rear reflective element substrate by applying a clear conductive pattern 38 a (such as an ITO or the like) on the rear surface of the rear reflective element substrate, and such as at a window formed in the silvering or reflective layer of the mirror reflective element assembly or cell. The conductive pattern may be connected directly to the conductive trace applied to the rear surface of the reflective element substrate. An outer LCD glass sheet 40 may be provided with a continuous conductive coating (such as an ITO or the like) on its rear surface 40 a and may be placed at the conductive pattern 38 a and spaced therefrom, such as via glass spacer beads or the like. The glass sheet 40 may include a jumper lead to connect to an appropriate trace or pad at the rear surface 20 a of rear substrate 20, or a connecting bump or pad may be formed in the trace to span the gap between the glass sheet 40 and the rear surface of the rear reflective element substrate and to connect the conductive trace to the continuous conductive coating on the glass sheet 40, without affecting the scope of the present invention. The mirror reflective element assembly or cell of the present invention thus may integrate an LCD display onto the reflective element or glass substrate of the reflective element assembly by using the reflective element or glass substrate of the mirror cell as the front glass sheet of the LCD display element.

Optionally, the printed circuit board of the mirror assembly of the present invention may include a display element along or partially along an edge of the board and may include one or more user-actuatable controls or buttons near or adjacent to the display element. The display element may be any type of display element, such as a vacuum fluorescent (VF) display element, a light emitting diode (LED) display element, an electroluminescent (EL) display element, a liquid crystal display (LCD) element, a video screen display element or the like, and may be operable to display various information (as discrete characters, icons or the like, or in a multi-pixel manner) to the driver of the vehicle, such as passenger side inflatable restraint (PSIR) information, tire pressure status, and/or the like. The buttons may be for actuating or controlling various accessories or controls or components associated with the vehicle, such as for a compass calibration setting or zone setting, a telematics actuation, a garage door opener, an electronic toll control (such as disclosed in U.S. Pat. No. 6,690,268, which is hereby incorporated herein by reference), and/or the like, or may be for switching the display between various functions or modes, without affecting the scope of the present invention.

Optionally, and as can be seen with reference to FIG. 1, electrochromic mirror reflective element assembly or cell 14 may include or may be associated with one or more switchable accessories, which may be toggled via actuation of one or more switches or buttons or inputs 42 at the front of the mirror assembly 10, such as along the bezel 13 of the mirror assembly 10. The user inputs or buttons may be for actuating or controlling various accessories or controls or components associated with the vehicle, such as for a compass calibration setting or zone setting, a telematics actuation, a garage door opener, an electronic toll control (such as disclosed in U.S. Pat. No. 6,690,268, which is hereby incorporated herein by reference), and/or the like, or may be for switching the display between various functions or modes, without affecting the scope of the present invention. Optionally, the user inputs may comprise touch sensors or proximity sensing inputs or the like, such as sensors of the types described in U.S. Pat. Nos. 6,001,486; 6,310,611; 6,320,282; 6,627,918; and 5,594,222; and/or U.S. Pat. Publication No. 2002/0044065, published Apr. 18, 2002, now U.S. Pat. No. 7,224,324; and/or U.S. patent application Ser. No. 10/933,842, filed Sep. 3, 2004, now U.S. Pat. No. 7,249,860; and/or PCT Application No. PCT/US03/40611, filed Dec. 19, 2003 and published on Jul. 15, 2004 as International Publication No. WO 2004/058540, which are hereby incorporated herein by reference, or may comprise inputs molded within the bezel of the mirror assembly, such as described in U.S. provisional applications, Ser. No. 60/535,559, filed Jan. 9, 2004 by Lindahl for MIRROR ASSEMBLY; and/or Ser. No. 60/553,517, filed Mar. 16, 2004 by Lindahl et al. for MIRROR ASSEMBLY, which are hereby incorporated herein by reference, or may comprise membrane type switches, such as described in U.S. provisional application Ser. No. 60/575,904, filed Jun. 1, 2004 by Uken for MIRROR ASSEMBLY FOR VEHICLE, which is hereby incorporated herein by reference; and/or the like, without affecting the scope of the present invention.

It is envisioned that the inputs 42 may be formed in the bezel 13 and that the circuitry applied to or disposed at the rear surface of the rear reflective element substrate may include one or more proximity sensors or sensing elements or antennae 44 (FIGS. 5 and 6) positioned along a lower edge of the rear surface of the rear reflective element substrate and generally corresponding with a respective one of the inputs 42. For example, the antenna or antennae or sensing elements may be adhered or clipped or otherwise secured to appropriate exposed pads or portions of the conductive trace 18 to position the antenna or antennae at the desired or appropriate location at the rear of the reflective element substrate. The antenna or antennae or sensing elements 44 may detect the presence of a person's finger at or near the respective input or inputs 42 and may actuate or control a display element or the like or may actuate or control or trigger the circuitry to switch or toggle the device associated with the input 42 in response to such a detection.

As shown in FIG. 5, the sensing elements 44 may be disposed along the lower or bottom edge of the rear reflective element substrate and may monitor a respective zone around the lower edge of the reflective element substrate or glass substrate. The sensing element or elements may provide a three dimensional cylinder of detection that extends along the bottom edge of the reflective element substrate and that encompasses the respective icon or input 42 at the bezel. As also shown in FIG. 5, the sensing element may comprise multiple separate sensing elements or antennae or antenna segments that may monitor separate zones corresponding to the respective inputs 42 at the bezel. The inputs 42 at the bezel thus may comprise a screen printed icon or character or the like at the bezel, and may not comprise any movable buttons or inputs or the like. As the user's finger approaches the desired input 42 (or spot or icon on the bezel), the corresponding antenna segment may detect the presence of the finger prior to contact as the finger enters the zone or cylinder of detection for that antenna segment. The electronic components and/or circuitry associated with that particular antenna may then toggle the device or accessory associated with the input, such as between an on/off status, a temperature or compass selection (such as for a temperature/compass display), a degrees F./degrees C. selection (such as for a temperature display), and/or the like.

Optionally, the controls may be operable to activate/deactivate/toggle/control an accessory in response to a detection of a user's finger or the like approaching the input or button region or sensing element at the mirror assembly. Because such inputs may be individual or separate proximity sensors or antennae positioned within the mirror assembly and not readily viewable or discernable by the driver or occupant of the vehicle, the mirror assembly may include a display or indicator that indicates the function of each input. Preferably, the mirror assembly may include a control or circuitry that selectively or occasionally activates a display to temporarily display the feature or function or accessory associated with the particular input or input region of the mirror assembly, such as in response to the user's finger or the like approaching the input area or the like. For example, it is further envisioned that when a user's finger is first detected as it approaches the input region (such as when the user's finger or the like is within a first threshold distance from one of the sensors, such as within about ¼ or ½ of an inch or thereabouts), the control or circuitry may activate a display (such as a display on demand type of display or transflective display that is viewable through the reflective element of the mirror assembly, such as described in U.S. Pat. Nos. 6,690,268; 5,668,663 and/or 5,724,187, and/or in U.S. patent application Ser. No. 10/054,633, filed Jan. 22, 2002, now U.S. Pat. No. 7,195,381, and/or Ser. No. 10/933,842, filed Sep. 3, 2004, now U.S. Pat. No. 7,249,860; and/or PCT Application No. PCT/US03/29776, filed Sep. 9, 2003 and published Apr. 1, 2004 as International Publication No. WO 2004/026633; and/or PCT Application No. PCT/US03/40611, filed Dec. 19, 2003 and published on Jul. 15, 2004 as International Publication No. WO 2004/058540, which are all hereby incorporated herein by reference) that indicates the accessory or feature or function associated with at least some or all of the inputs along the bezel or other region of the mirror assembly. The display may list or indicate the features (such as via text or icons or other indicia) at areas of the reflective element that are near to or generally adjacent to the respective inputs or input regions.

When the user then moves his or her finger to touch or contact the desired or appropriate input (or may move the finger closer to the input region or sensor, such as within a second threshold distance from the sensor that is smaller than the first threshold distance), such as at the bezel or the like, the detection of the contact (or of a closer proximity of the finger) may cause the control to activate/deactivate or toggle/adjust or control the accessory or feature or function associated with that input or input region. As the user's finger is moved closer to or contacts the selected input region, the displays for the other inputs may deactivate so that only the display for the selected input remains viewable by the user. Optionally, the detection of the closer proximity (such as within the second threshold distance or touching) may cause other menus or the like to appear at the mirror assembly, whereby the user may toggle or scroll through the menus to accomplish the desired task or activate/deactivate/adjust the desired or appropriate accessory or function or feature. The user thus may activate/deactivate/toggle/adjust/control the accessory or function or feature associated with the selected input or may scroll through a menu shown in the display at the reflective element.

Optionally, it is envisioned that the control or circuitry may initially activate a display element or display device associated with one of the inputs or buttons or sensor regions, such that as the user's finger approaches a particular input or button or sensor region (such as when the user's finger is within a threshold distance of the input, such as within approximately ¼ or ½ inches or thereabouts of the input or input region), the control or circuitry may activate the respective display that indicates the accessory or feature or function associated with that particular input or input region or sensor. The user thus may move their finger along the front of the mirror assembly (and over and along the separate/distinct sensors or input regions) and view the display or information for the accessory or feature or function associated with each region or input. When the user's finger is located at the desired function, the user may then contact the input region (or may move the finger closer to the input region or sensor), whereby the detection of the contact (or of a closer proximity of the finger) may cause the control to activate/deactivate or toggle/adjust or control the accessory or feature or function associated with that input or input region, or may cause other menus or the like to appear at the mirror assembly, such as described above.

The present invention thus provides for the circuitry and electronic components to be kept substantially or entirely at the rear of the mirror reflective element assembly or cell, yet provides for front switching of an accessory or the like. The present invention provides for such front switching in response to a touch or approach of a designated area at the bezel (or elsewhere around the mirror assembly), without any buttons and associated wires or leads being needed at the bezel area. Also, because the proximity sensors or antennae or antenna segments are positioned at the rear of the reflective element or cell, no soldering or otherwise connecting of leads or wires to the buttons at the front of the mirror assembly is required. The present invention thus provides for such functions with a bezel that provides a reduced cost and complexity of the bezel and the casing of the mirror assembly.

The electronic components or circuitry and/or accessories may receive power from the vehicle power source, whereby the vehicle may include wiring to the mirror assembly, such as two wires for power and ground to the mirror assembly. Optionally, the vehicle may incorporate a telematics system, such as an ONSTAR® system or the like, which may have circuitry in the instrument panel of the vehicle. The telematics circuitry may include wires connected to the buttons or inputs at the mirror assembly that provide a toggling function to the telematics system in response to actuation of the respective telematics inputs. It is envisioned that the same wiring to the mirror assembly may also be selectably usable to provide for signal transmission from the telematics system to the mirror assembly, such as for a global positioning system (GPS) function or the like.

Optionally, the power and ground connection may only be provided to the mounting bracket, which may provide an electrical contact to the mirror circuitry via an electrical contact or wiper action at the ball and socket connection of the mounting arm or mounting arrangement of the mirror assembly. For example, the signals may be provided via a mounting arrangement utilizing aspects of the mounting arrangements described in U.S. patent application Ser. No. 10/032,401, filed Dec. 20, 2001, now U.S. Pat. Publication No. US2002/0088916A1, published Jul. 11, 2002, now U.S. Pat. No. 6,877,709; and/or PCT Application No. PCT/US2004/015424, filed May 18, 2004 and published on Dec. 2, 2004, as International Publication No. WO 2004/103772, and/or U.S. provisional application Ser. No. 60/609,642, filed Sep. 14, 2004 by Karner for MOUNTING ASSEMBLY FOR MIRROR AND METHOD OF MAKING SAME, which are hereby incorporated herein by reference, or may utilize electrical connection principles of the type described in International Publication No. WO 2003/095269 A3, published Nov. 20, 2003 for REARVIEW MIRROR ASSEMBLIES, which is hereby incorporated herein by reference. The signals to control the accessories or circuitry of the mirror assembly may optionally be provided through an infrared link between the mounting bracket and the circuitry in the mirror, such as described in U.S. patent application Ser. No. 10/456,599, filed Jun. 6, 2003, now U.S. Pat. No. 7,004,593, which is hereby incorporated herein by reference.

Optionally, and as described in U.S. Pat. No. 5,724,187, incorporated above, a mirror reflective element assembly 101 may include front and rear substrates that may be flush or offset relative to one another. For example, and with reference to FIGS. 8 and 9A-C, an exposed portion of the conductive electrode coatings 104, 104′ may be provided through displacement in opposite directions relative to one another—i.e., laterally from, but parallel to, the cavity which is created by the substrates 102, 103 and the sealing means 105 of the substrates 102, 103 onto which the bus bars may be affixed or adhered. (See FIG. 9A.) In addition, substrates 102, 103 may be off-set to provide an exposed portion of the conductive electrode coatings 104, 104′ through displacement in opposite directions relative to one another followed by perpendicular displacement relative to one another. (See FIG. 9B.) The dimensions of substrates 102, 103 may also be such that, for example, substrate 102 may have a greater width and/or length than substrate 103. Thus, simply by positioning substrates 102, 103 in spaced-apart relationship and so that their central portions are aligned will allow for peripheral edges of the substrate with greater dimensions to extend beyond the peripheral edges of the substrate with smaller dimensions. Thus, a portion of conductive electrode coating 104 or 104′ will be exposed, depending on whichever of substrates 102, 103 is dimensioned with a larger width and/or length. (See FIG. 9C.)

An exposed portion of the conductive electrode coatings 104, 104′ may also be provided in a flush design, where the substrates 102, 103 are sized and shaped to like dimensions. In such a flush design, the first substrate 102 and the second substrate 103 may each be notched at appropriate positions along their respective edges. The notches so provided present convenient areas for bus bars and/or point contacts to which are connected or affixed electrical leads 110 for the introduction of an applied potential thereto.

It may also be desirable to apply a layer of reflective material onto the inward surface of substrate 103, and with substrate 103 notched in at least one appropriate position along its edges. In this way, direct access is available to the conductive electrode coated inward surface of substrate 102. Likewise, substrate 102 may be notched at a position appropriately spaced from the notch or notches on substrate 103 to provide access to the conductive electrode coated inward surface of substrate 103. These notches provide convenient areas for electrical leads to be connected or affixed, and allow for such connection or affixation to be made within the overall dimensions of the mirror assembly. For example, one or both of the substrates 102, 103 may be notched along one or more edges, and bus bars may then be affixed over the exposed portion of conductive electrode coatings 104, 104′ of substrates 102, 103. Electrical leads may then be joined to the bus bars. The electrical connection may be made to the inward surfaces of substrates 102, 103 without requiring further electrical connection on the peripheral edge of the mirror assembly. As such, the electrical connection to conductive electrode coatings 104, 104′ will be hidden from view by the reflective element and/or the mirror case or housing.

Alternatively, one or more localized lobe(s) may be provided at appropriate positions along the respective edges of substrates 102, 103 to facilitate direct access to the conductive coated inward surfaces of substrates 102, 103.

The bus bars may also comprise thin metal films, preferably with a thickness within the range of about 500 Å to about 50,000 Å or greater. These thin metal film bus bars may be deposited onto conductive electrode 104 and/or 104′ by vacuum deposition, such as by evaporation or sputtering, and typically have a width within the range of about 0.05 mm to about 6 mm (and preferably with a thickness in the range of 0.05 μm to about 5 μm or greater) and are inboard from the perimeter edge of the substrate.

To form the thin metal film bus bars, a mask may be affixed over the central region of the substantially transparent conductive electrode coated substrate leaving at least a portion, and preferably most, of the perimeter region unmasked. Then a thin film of metal, such as chromium and/or silver, or other metals such as copper, titanium, steel, nickel-based alloys, and the like, may be deposited using a vacuum deposition process across the entire surface, coating both the masked central region and the unmasked perimetal region. Thereafter, the mask may be removed leaving the central region of the substrate transparent and with a conducting thin metal film bus bar deposited on at least a portion of the perimetal region. For manufacturing economy, it may be desirable to establish thin metal film bus bars on the inward surface of substrate 102, conductive electrode coating 104′ and electrochromic solid film 107 in a unitary vacuum deposition process step. Thus, it may be convenient to overlay in central alignment, for example, substrate 103 (being uncoated glass) onto the substantially transparent conductive electrode coated surface of substrate 102, where substrate 103 is sized and shaped 30 about 2 mm to about 4 mm smaller in both length and width than substrate 102 (see e.g., FIG. 9C). A peripheral edge of substrate 102 of about 2 mm to about 4 mm will then extend beyond the peripheral edge of substrate 103. In this instance, substrate 102 is made, for example, from ITO-coated glass, and substrate 103 is made from clear soda-lime glass. With this configuration, a vacuum deposition process may be used to deposit a thin metal film and, optionally, a metal oxide thereover, across the entire surface.

Upon completion of the deposition process, the substrates 102, 103 may be separated from one another. The formation of a thin metal film bus bar consisting of a chromium/silver coating about the peripheral edge of substrate 102 may then be seen where, because of its smaller dimensions, substrate 103 has served the role of a mask to the major, central region of substrate 102 during deposition. That is, when substrate 103 is removed, the major, central region of substrate 102 has not been coated during the deposition and the transparency of the major, central region of substrate 102 is maintained. Because this thin metal film bus bar is highly conductive and extends about the entire periphery of substrate 102, electric potential may be supplied by means of a point electrical contact (optionally with local removal of any metal oxide) without the need for a large metal clip or ribbon connector wire as has been conventionally used heretofore. Moreover, because the thin metal film bus bar consists of a chromium/silver coating it forms a highly reflective perimeter coating which may be used to conceal any seal and/or electrical connection for the electrochromic cell. [See U.S. Pat. No. 5,060,112 (Lynam)]

Also, whether the sealing means 105 is a single seal or a double seal, it may be desirable for the seal material to comprise a cured conductive adhesive so that the seal, or at least a portion thereof, may provide, in whole or at least in part, an electrical bus bar function around the perimeter of a substrate of the assembly. When using such a combined seal and bus bar, care should be taken to avoid electrically shorting the inward facing surfaces of substrates 102 and 103. To obviate this, a seal construction, such as that shown in FIG. 10A, may be used. With reference to FIG. 10A, substrates 220 and 230 are coated on their inwardly facing surfaces with electrical conductor electrodes 220′ and 230′. The substrates 220, 230 are mated together with the compound seal 250. The compound seal 250 includes a conducting seal layer 250A (formed, for example, of a conducting epoxy such as is described below) and a non-conducting, electrically insulating seal layer 250B (formed, for example, of a conventional, non-conducting epoxy), which serves to insulate the two conducting electrodes from electrically shorting via conducting seal layer 250A. Since the compound seal 250 essentially circumscribes the edge perimeter of the part, the conducting seal layer 250A (to which electrical potential may be connected to via the electrical lead 290) serves as an electrically conductive bus bar that distributes applied electrical power more evenly around and across the electrochromic medium (not shown) sandwiched between the substrates 220 and 230.

Where the electrical conductor electrode 220′, 230′ on at least one of the opposing surfaces of the substrates 220, 230 is removed (or was never coated) in the region of the peripheral edge (as shown in FIG. 10B), a unitary conducting seal (as opposed to the compound seal of FIG. 10A) may be used. Reference to FIG. 10B shows the electrically conducting seal 250A joining the electrical conductor electrode 230′ on the surface of substrate 230 to a bare, uncoated surface of opposing substrate 220. Since the contact area of the conducting seal layer 250A to the substrate 220 is devoid of the electrical conductor electrode 220′, the conducting seal layer 250A does not short the electrodes 220′ and 230′. Conducting seal layer 250A serves the dual role of bus bar and seal, yielding economy and ease in device fabrication and production. Conducting seal layer 250A may form a single seal for the cell or may be one of a double seal formed, for example, when a conventional, non-conducting epoxy is used inboard of that conducting seal.

Such a construction is particularly amenable to devices, such as those depicted in FIG. 8. For instance, in a rearview mirror, a fixture can form a mask around the edge substrate perimeter, while an adhesion layer of chromium followed by a reflector layer of aluminum followed by an electrochromic layer of tungsten oxide are deposited. Once removed from such a coating fixture, the edges, as masked by the coating fixture, are uncoated and present a bare glass surface for joining via a conductive epoxy seal to an opposing transparent conductor coated substrate. In such a configuration, the conductive seal can serve as a bus bar for the transparent conductor coated substrate it contacts without shorting to the reflector/adhesion layers on the opposite substrate.

As described supra, it may be advantageous to construct electrochromic mirrors whose reflective element is located within the laminate assembly. This may be achieved by coating the inward surface of substrate 103 with a layer of reflective material, such as silver, so that the silver coating (along with any adhesion promoter layers) is protected from the outside environment. For example, a layer of reflective material may be vacuum deposited onto the inward surface of substrate 103 in one and the same process step as the subsequent deposition of the electrochromic solid film 107 onto substrate 103. This construction and process for producing the same not only becomes more economical from a manufacturing standpoint, but also achieves high optical performance since uniformity of reflectance across the entire surface area of the mirror is enhanced. The thin film stack [which comprises the electrochromic solid film 107 (e.g., tungsten oxide), the layer of reflective material (e.g., silver or aluminum) and any undercoat layers between the layer of reflective material and substrate 103] should have a light reflectance within the range of at least about 70% to greater than about 80%, with a light transmission within the range of about 1% to about 20%. Preferably, the light transmission is within the range of about 3% to about 20%, and more preferably within the range of about 4% to about 8%, with a light reflectance greater than about 80%.

The inward facing surface of substrate 103 may be coated with a multi-layer partially transmitting/substantially reflecting conductor comprising a partially transmitting (preferably, in the range of about 1% to about 20%)/substantially reflecting (preferably, greater than about 70% reflectance, and more preferably, greater than about 80 reflectance) metal layer (preferably, a silver or aluminum coating) that is overcoated with an at least partially conducting transparent conductor metal oxide layer [comprising a doped or undoped tin oxide layer, a doped or undoped indium oxide layer (such as indium tin oxide) or the like]. Optionally, an undercoating metal oxide (or another at least partially transmitting metal compound layer, such as a metal nitride like titanium nitride) may be included in the stack which comprises the multilayer conductor. This multi-layer conductor functions as the reflective element, and can be overcoated with electrochromic solid film 107 during fabrication of an electrochromic mirror incorporating on demand displays.

Alternatively, the multi-layer conductor described supra may be used on the inward surface of substrate 103, with the electrochromic solid film 107 coated onto the inward surface of substrate 102.

A light reflectance of at least 70% (preferably, at least 80%) for the reflective element to be used in an electrochromic mirror incorporating on demand displays is desirable so that the bleached (unpowered) reflectivity of the electrochromic mirror can be at least 55% (preferably, at least 65%) as measured using SAE J964a, which is the recommended procedure for measuring reflectivity of rearview mirrors for automobiles. Likewise, a transmission through the reflective element of, preferably, between about 1 to 20% transmission, but not much more than about 30% transmission (measured using Illuminant A, a photopic detector, and at near ‘normal incidence) is desirable so that emitting displays disposed behind the reflective element of the electrochromic mirror are adequately visible when powered, even by day but, when unpowered and not emitting, the displays (along with any other components, circuitry, backing members, case structures, wiring and the like) are not substantially distinguishable or visible to the driver and vehicle occupants.

Optionally, the outermost surface of the substrate (i.e., the surface contacted by the outdoor elements including rain, dew and the like when, for example, the substrate forms the outer substrate of an interior or exterior rearview mirror for a motor vehicle constructed) can be adapted to have an anti-wetting property. For example, the outermost glass surface of an exterior electrochromic rearview mirror can be adapted so as to be hydrophobic. This reduces wetting by water droplets and helps to obviate loss in optical clarity in the reflected image off the exterior mirror when driven during rain and the like, caused by beads of water forming on the outermost surface of the exterior electrochromic mirror assembly. Preferably, the outermost glass surface of the electrochromic mirror assembly is modified, treated or coated so that the contact angle θ (which is the angle that the surface of a drop of liquid water makes with the surface of the solid anti-wetting adapted outermost surface of the substrate it contacts) is preferably greater than about 90 degrees, more preferably greater than about 120 degrees and most preferably greater than about 150 degrees. The outermost surface of the substrate may be rendered anti-wetting by a variety of means including ion bombardment with high energy, high atomic weight ions, or application thereto of a layer or coating (that itself exhibits an anti-wetting property) comprising an inorganic or organic matrix incorporating organic moieties that increase the contact angle of water contacted thereon. For example, a urethane coating incorporating silicone moieties (such as described in U.S. Pat. No. 5,073,012) may be used. Also, to enhance durability, diamond-like carbon coatings, such as are deposited by chemical vapor deposition processes, can be used as an anti-wetting means on, for example, electrochromic mirrors, windows and devices.

Optionally, the conductive trace and electronic components or circuitry at the reflective element substrate of the mirror assembly may provide or include or be associated with other accessories, such as a rain sensor (such as the type disclosed in commonly assigned U.S. Pat. Nos. 6,320,176; 6,353,392 and 6,313,454, which are hereby incorporated herein by reference), an image sensor (such as a video camera, such as a CMOS imaging array sensor, a CCD sensor or the like, such as the types disclosed in commonly assigned, U.S. Pat. Nos. 5,550,677; 6,097,023 and 5,796,094, which are hereby incorporated herein by reference), a temperature sensor (such as a contact temperature sensor for measuring the temperature at or of the windshield), an antenna, a compass (such as the types disclosed in U.S. patent application Ser. No. 10/456,599, filed Jun. 6, 2003, now U.S. Pat. No. 7,004,593, which is hereby incorporated herein by reference) or any other sensor or accessory or device. For example, the mirror assembly may include a forward facing video image sensor or system, which may include an intelligent rain sensor (such as the type disclosed in commonly assigned U.S. Pat. Nos. 6,320,176; 6,353,392 and 6,313,454, which are hereby incorporated herein by reference), an image or vision system (including an imaging sensor, such as a video camera, such as a CMOS imaging array sensor, a CCD sensor or the like, such as the types disclosed in commonly assigned, U.S. Pat. Nos. 5,550,677; 6,097,023 and 5,796,094, and U.S. patent application Ser. No. 10/422,378, filed Apr. 24, 2003, now U.S. Pat. No. 6,946,978, which are hereby incorporated herein by reference), an intelligent headlamp controller (such as the type disclosed in U.S. Pat. No. 5,796,094 and/or in U.S. patent application Ser. No. 10/355,454, filed Jan. 31, 2003, now U.S. Pat. No. 6,824,281, which are hereby incorporated herein by reference), an intelligent lane departure warning system, such as the type disclosed in U.S. patent application Ser. No. 10/427,051, filed Apr. 30, 2003, now U.S. Pat. No. 7,038,577, which is hereby incorporated herein by reference, and/or the like. Optionally, the mirror assembly of the present invention may include one or more displays, such as a text display, an iconistic display, a display on demand type display (such as may be implemented with a transflective reflective element, such as described in U.S. Pat. Nos. 6,690,268; 5,668,663 and 5,724,187, which are hereby incorporated by reference herein), a video or touch screen interface display, or the like, and/or one or more sensors or other accessories, such as a biometric imager, such as for fingerprint authentication or the like, an infrared sensor, such as a zonal temperature sensor, such as suitable for an auto climate control, a forward facing image sensor, such as described above, a rearward facing image sensor (such as for biometric imaging (such as for face recognition, iris recognition or the like), seat height or position detection, drowsiness detection, safety/restraints, object detection and position, emergency response image capture system, intrusion detection or the like), and/or an electronic field sensor (such as the type disclosed in commonly assigned U.S. Pat. No. 6,768,420, which is hereby incorporated herein by reference) and/or the like. The display and/or accessories may be associated with a communication system, a speaker, a telematics module (which may include a GPS module, a wireless communication module, an human/machine interface (HMI), a display, such as an LED display, a dot matrix display, an alpha numeric display, a video display or the like, and/or a microphone, which may be operable for speech or voice recognition, noise reduction or noise cancellation), a humidity sensor, a remote keyless entry sensor, a tire pressure monitoring system (TPMS) (such as the types described in U.S. Pat. Nos. 6,731,205; 6,294,989; 6,124,647; 6,445,287; and/or 6,472,979, and/or U.S. provisional application Ser. No. 60/611,796, filed Sep. 21, 2004 by O'Brien for TIRE PRESSURE ALERT SYSTEM, which are hereby incorporated herein by reference), an electronic toll collection sensor, an intelligent headlamp control, user interface controls (such as buttons, switches or the like for controlling various accessories of the vehicle, such as a sunroof, a communication system, lamps, security systems, displays or the like) or any other accessories, sensors, lights, indicators, displays or the like which may be suitable for mounting or positioning at or within the rearview mirror assembly.

The accessories or components of the rearview mirror assembly may be connected to the vehicle electronic or communication systems and may be connected via various protocols or nodes, such as Bluetooth, SCP, UBP, J1850, CAN J2284, Fire Wire 1394, MOST, LIN and/or the like, depending on the particular application of the rearview mirror assembly of the present invention. The rearview mirror assembly may be electronically integrated with the vehicle electrical and/or control systems. For example, the rearview mirror assembly may connect to a sunroof control, rain sensor control, mass motion sensor, roof lighting control, microphone/cell phone control, climate control, and/or the like.

Therefore, the rearview mirror assembly and mirror reflective element assembly of the present invention provides a mirror reflective element assembly that includes the conductive trace and electronic components or circuitry applied directly to or integrated with the rear surface of the reflective element substrate of the mirror reflective element assembly or cell. The present invention thus provides a circuitry on glass arrangement and thus obviates the need for a separate rigid board or substrate for receiving circuitry thereon, and also obviates the need for an attachment plate and associated connectors for attaching such a printed circuit board to the rear of the reflective element assembly or cell. The present invention thus provides a compact and lightweight mirror reflective element assembly that provides enhanced assembly processing and minimizes electrical wiring and connections that may have to be made to connect the circuitry to various components or accessories associated with the mirror reflective element assembly.

Changes and modifications in the specifically described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law. 

The invention claimed is:
 1. A method of manufacturing a reflective element for a rearview mirror assembly of a vehicle, said method comprising: providing a front glass substrate and a rear glass substrate; wherein said front glass substrate has a first surface and a second surface opposite said first surface, and wherein a transparent electrically conductive layer is disposed at said second surface; wherein said rear glass substrate has a third surface and a fourth surface opposite said third surface, and wherein an electrically conductive mirror reflector is disposed at said third surface; establishing an uncured trace material at least at said rear glass substrate; establishing an uncured seal material along at least one of (i) a perimeter region of said second surface of said front glass substrate and (ii) a perimeter region of said third surface of said rear glass substrate; joining said front and rear glass substrates with said uncured seal material disposed therebetween; curing said uncured seal material and said uncured trace material via a common curing process, wherein said curing of said uncured trace material forms an electrically conductive trace at said rear glass substrate and wherein said curing of said uncured seal material forms a perimeter seal of said reflective element; wherein said electrically conductive trace is in electrical continuity with said electrically conductive mirror reflector; and establishing a perimeter coating at a perimeter region of said second surface of said front glass substrate, wherein said perimeter coating comprises a reflective perimeter coating.
 2. The method of claim 1, wherein said reflective perimeter coating comprises a metal thin film.
 3. The method of claim 2, wherein said reflective perimeter coating is electrically conductive.
 4. The method of claim 3, wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 5. The method of claim 1, wherein said uncured seal material comprises an epoxy.
 6. The method of claim 5, wherein said uncured trace material comprises a silver epoxy.
 7. The method of claim 1, wherein said common curing process comprises heating said uncured seal material and said uncured trace material.
 8. The method of claim 1, wherein said common curing process comprises one of (i) an air curing process and (ii) an oven curing process.
 9. The method of claim 1, wherein establishing an uncured trace material comprises establishing an uncured trace material at least partially at said fourth surface of said rear glass substrate.
 10. The method of claim 9, comprising establishing a non-conductive layer at one of (i) said uncured trace material at said fourth surface of said rear glass substrate and (ii) said electrically conductive trace at said fourth surface of said rear glass substrate.
 11. The method of claim 1, comprising at least one of (i) disposing an electronic component at said uncured trace material and (ii) disposing circuitry at said uncured trace material.
 12. The method of claim 1, wherein establishing an uncured trace material comprises establishing an uncured trace material directly at least at said fourth surface of said rear glass substrate.
 13. The method of claim 1, wherein said method is for manufacturing a reflective element for an electrochromic rearview mirror assembly of a vehicle.
 14. The method of claim 1, wherein said method is for manufacturing a reflective element for an electrochromic interior rearview mirror assembly of a vehicle.
 15. The method of claim 1, wherein, when joined together, no part of said rear glass substrate protrudes beyond any part of said front glass substrate.
 16. A method of manufacturing a reflective element for a rearview mirror assembly of a vehicle, said method comprising: providing a front glass substrate and a rear glass substrate; wherein said front glass substrate has a first surface and a second surface opposite said first surface, and wherein a transparent electrically conductive layer is disposed at said second surface; wherein said rear glass substrate has a third surface and a fourth surface opposite said third surface, and wherein an electrically conductive mirror reflector is disposed at said third surface; establishing a reflective perimeter coating at a perimeter region of said second surface of said front glass substrate; establishing an uncured trace material at least at said rear glass substrate; establishing an uncured seal material along at least one of (i) a perimeter region of said second surface of said front glass substrate and (ii) a perimeter region of said third surface of said rear glass substrate; wherein said uncured seal material comprises an epoxy; joining said front and rear glass substrates with said uncured seal material disposed therebetween; curing said uncured seal material and said uncured trace material via a common curing process, wherein said curing of said uncured trace material forms an electrically conductive trace at said rear glass substrate and wherein said curing of said uncured seal material forms a perimeter seal of said reflective element; and wherein said electrically conductive trace is in electrical continuity with said electrically conductive mirror reflector.
 17. The method of claim 16, wherein said uncured trace material comprises a silver epoxy.
 18. The method of claim 16, wherein establishing an uncured trace material comprises establishing an uncured trace material at least partially at said fourth surface of said rear glass substrate.
 19. The method of claim 18, comprising establishing a non-conductive layer at one of (i) said uncured trace material at said fourth surface of said rear glass substrate and (ii) said electrically conductive trace at said fourth surface of said rear glass substrate.
 20. The method of claim 16, comprising at least one of (i) disposing an electronic component at said uncured trace material and (ii) disposing circuitry at said uncured trace material.
 21. The method of claim 16, wherein establishing an uncured trace material comprises establishing an uncured trace material directly at least at said fourth surface of said rear glass substrate.
 22. The method of claim 16, wherein said method is for manufacturing a reflective element for an interior rearview mirror assembly of a vehicle.
 23. The method of claim 16, wherein, when joined together, no part of said rear glass substrate protrudes beyond any part of said front glass substrate.
 24. The method of claim 16, wherein said reflective perimeter coating comprises a metal thin film, and wherein said reflective perimeter coating is electrically conductive, and wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 25. The method of claim 16, wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 26. A method of manufacturing a reflective element for a rearview mirror assembly of a vehicle, said method comprising: providing a front glass substrate and a rear glass substrate; wherein said front glass substrate has a first surface and a second surface opposite said first surface, and wherein a transparent electrically conductive layer is disposed at said second surface; wherein said rear glass substrate has a third surface and a fourth surface opposite said third surface, and wherein an electrically conductive mirror reflector is disposed at said third surface; establishing a reflective perimeter coating at a perimeter region of said second surface of said front glass substrate; establishing an uncured trace material at least at said rear glass substrate; establishing an uncured seal material along at least one of (i) a perimeter region of said second surface of said front glass substrate and (ii) a perimeter region of said third surface of said rear glass substrate; joining said front and rear glass substrates with said uncured seal material disposed therebetween; curing said uncured seal material and said uncured trace material via a common curing process, wherein said common curing process comprises heating said uncured seal material and said uncured trace material, and wherein said curing of said uncured trace material forms an electrically conductive trace at said rear glass substrate and wherein said curing of said uncured seal material forms a perimeter seal of said reflective element; and wherein said electrically conductive trace is in electrical continuity with said electrically conductive mirror reflector.
 27. The method of claim 26, wherein said uncured seal material comprises an epoxy.
 28. The method of claim 26, wherein said uncured trace material comprises a silver epoxy.
 29. The method of claim 26, wherein establishing an uncured trace material comprises establishing an uncured trace material at least partially at said fourth surface of said rear glass substrate.
 30. The method of claim 29, comprising establishing a non-conductive layer at one of (i) said uncured trace material at said fourth surface of said rear glass substrate and (ii) said electrically conductive trace at said fourth surface of said rear glass substrate.
 31. The method of claim 26, comprising at least one of (i) disposing an electronic component at said uncured trace material and (ii) disposing circuitry at said uncured trace material.
 32. The method of claim 26, wherein establishing an uncured trace material comprises establishing an uncured trace material directly at least at said fourth surface of said rear glass substrate.
 33. The method of claim 26, wherein said method is for manufacturing a reflective element for an interior rearview mirror assembly of a vehicle.
 34. The method of claim 26, wherein, when joined together, no part of said rear glass substrate protrudes beyond any part of said front glass substrate.
 35. The method of claim 26, wherein said reflective perimeter coating comprises a metal thin film, and wherein said reflective perimeter coating is electrically conductive, and wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 36. The method of claim 26, wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 37. A method of manufacturing a reflective element for a rearview mirror assembly of a vehicle, said method comprising: providing a front glass substrate and a rear glass substrate; wherein said front glass substrate has a first surface and a second surface opposite said first surface, and wherein a transparent electrically conductive layer is disposed at said second surface; wherein said rear glass substrate has a third surface and a fourth surface opposite said third surface, and wherein an electrically conductive mirror reflector is disposed at said third surface; establishing a reflective perimeter coating at a perimeter region of said second surface of said front glass substrate; wherein said reflective perimeter coating comprises a metal thin film, and wherein said reflective perimeter coating is electrically conductive; establishing an uncured trace material at least at said rear glass substrate; establishing an uncured seal material along at least one of (i) a perimeter region of said second surface of said front glass substrate and (ii) a perimeter region of said third surface of said rear glass substrate; joining said front and rear glass substrates with said uncured seal material disposed therebetween; wherein, when joined together, no part of said rear glass substrate protrudes beyond any part of said front glass substrate; curing said uncured seal material and said uncured trace material via a common curing process, wherein said curing of said uncured trace material forms an electrically conductive trace at said rear glass substrate and wherein said curing of said uncured seal material forms a perimeter seal of said reflective element; wherein said electrically conductive trace is in electrical continuity with said electrically conductive mirror reflector; and wherein said reflective perimeter coating conceals said perimeter seal from view through said front glass substrate.
 38. The method of claim 37, wherein at least one of (i) said uncured seal material comprises an epoxy and (ii) said uncured trace material comprises a silver epoxy.
 39. The method of claim 37, wherein said common curing process comprises heating said uncured seal material and said uncured trace material.
 40. The method of claim 37, comprising at least one of (i) disposing an electronic component at said uncured trace material and (ii) disposing circuitry at said uncured trace material.
 41. The method of claim 37, wherein said method is for manufacturing a reflective element for an electrochromic rearview mirror assembly of a vehicle.
 42. The method of claim 41, wherein said electrochromic rearview mirror assembly comprises an electrochromic interior rearview mirror assembly. 